치관 확장술을 통한 변형된 수동적 맹출의 치료

Purpose: Passive eruption is characterized by the apical shift of the dentogingival junction. As this occurs, the length of the clinical crown increases as the epithelial attachment migrates apically. Altered passive eruption occurs when the margin of gingiva is malpositioned incisally on the anatomic crown in adulthood and results in excessive gingiva. The purpose of this article is to evaluate esthetic results of crown lengthening procedure in altered passive eruption.s. Materials and Methods: Three patients who complained "My front teeth look too short" were included. Bone sounding with periodontal probe revealed that alveolar bone crest was close to CEJ. Based on the diagnostic information, a diagnosis of altered passive eruption was made. They were performed apically positioned flap procedure with osseous resection. Results: Six months later, all patients achieved favorable esthetic results and gingival margins were healthy and stable. Conclusion: When the diagnostic procedures reveal alveolar bone crest levels approximating the CEJ, apically positioned flap procedure with osseous resection is indicated

임산부의 치주질환 활성도와 조산과의 상관관계에 관한 연구

Purpose We designed this study for the purpose of determining the relationship between periodontal disease activity and PLBW, using the evaluation of probing pocket depth, loss of attachment, gingival index, gingival crevicular fluid amount and subgingival microflora. Methods A total of 100 volunteer mothers(mean age 30.44) at the Department of Obstetrics and Gynecology Seoul National University Hospital were selected for this study.Pregnancy outcomes were categorized into cases and controls in two ways. our definition was based on the following; Group 1 : Any PLBW cases Vs. All NBW controls Group 2 : PLBW cases Vs. NBW controls A periodontal exam was performed on the Ramfjord( #16, 21, 24, 36, 41, 44) teeth and Clinical evaluation consisted of probing pocket depth, loss of attachment, gingival index and gingival crevicular fluid amount. Subgingival plaque samples were collected by three sterile #35 paper points. The total number of anaerobic colonies and aerobic bacteria were enumerated after incubation. Antisera to P. gingivalis, P. intermedia, A. actinomycetemcomitans were produced in white rabbits with live whole cells suspensions. The specific fluorescent bacteria obtained by immunofluorescence and total cell counts obtained by dark-field microscopy were counted on four fields. The percent of each specific microorganism in the total cell count was determined. Results Any PLBW and PLBW cases showed significantly greater probing depth and attachment loss than all NBW and NBW controls. Cases group had significantly increased anaerobic bacterial counts compared with control group and no differences in the other microbes. This study confirmed that periodontal disease is a statistically significant risk factor for PLBW by investigating clinical parameters and subgingival plaque analysis.이 연구는 1996년도 서울대학교 병원지정연구비 지원에 의한 결과입니다

차폐막 노출이 발치 후 치조제 보존술의 결과에 미치는 영향에 관한 임상적 연구

Purpose: Following tooth extraction caused by severe periodontitis, alveolar ridge dimension lose their original volume. To reduce the alveolar ridge dimension, the ridge preservation technique has been introduced and tested in many clinical studies with membrane alone or membrane plus graft, achieving reduced ridge loss compared to extraction only. The aim of the present clinical study was to compare the post-extraction dimensional changes in the membrane exposure group to non-exposure group during healing period following ridge preservation technique. Methods: Ridge preservation was performed in 44 extraction sites. After extraction, deproteinized bovine bone mineral coated with synthetic oligopeptide (Ossgen-) or deproteinized bovine bone mineral (Bio-) was implanted into the socket. A collagen membrane (Bio-) was trimmed to cover the socket completely and applied to the entrance of the socket. Four clinical parameters were compared between baseline and 6 months. Results: During healing period, membrane exposure was observed at 19 sites. At the re-entry, hard newly formed tissue were observed at the ridge preservation site. The grafted socket sites were well preserved in their volume dimension. In both groups, horizontal ridge width was reduced and vertical height was increased. There were not statistically significant differences in horizontal (-1.32 mm vs -1.00 mm) and vertical ridge change (2.24 mm vs 2.37 mm at buccal crest, 1.36 mm vs. 1.53 mm at lingual crest) between two groups. Conclusions: The ridge preservation approach after tooth extraction effectively prevented resorption of hard tissue ridge in spite of membrane exposure during healing period.이 연구는 (주)나이벡의 지원으로 수행되었습니다

Mechanism of Translational Inhibition by MicroRNA

DoctorMicroRNAs (miRNAs) are 21~24-nt small noncoding RNAs that play a key role in the post-transcriptional gene silencing in metazoan animals, plants and protozoa. Many of the animal miRNAs are phylogenetically conserved, and ~55% of nematode miRNAs, for example, have homologues in humans, indicating that miRNAs have important roles throughout animal evolution. Indeed, mammalian miRNAs are bioinformatically predicted to control ~30% of the protein-coding genes, and participate in several biological processes such as development, differentiation, proliferation, apoptosis, metabolic control, metastasis, etc.miRNAs usually function as guidance in the post-transcriptional gene regulation by base-pairing with the 3-UTR of the target mRNAs. For this, Argonaute proteins, key factors in the small RNA-mediated gene silencing, form an effector protein complex called the RNA-induced silencing complex or the miRNA-containing ribonucleoprotein complex. Many miRNAs degrade the targeted mRNAs by promoting their deadenylation and/or decappig, resulting in the repression of gene expression. Also, many reports have indicated that miRNAs participate in the gene silencing by decreasing the translation of mRNAs. Several studies have suggested that miRNAs can reduce translation of their target mRNAs at the post-initiation stage (i.e., the elongation step), based on observations that miRNAs co-migrate with polyribosomes and their polysomal distributions are not altered during the gene repression. Recently, it has been suggested that the translational repression by miRNAs occurs at the initiation step of translation, and particularly that the 5 mRNA cap structure is critical for the miRNA-mediated translational gene silencing, probably via the competition of Ago2 with a cap-binding protein eIF4E for the mRNA cap structure. However, the molecular basis of this silencing is unclear.Here, I show that human Ago2 associates with the cap-binding protein complex and this association is mediated by human eIF4GI, a scaffold protein required for the translation initiation. Cap-pulldown assays show that Ago2 proteins form a complex with the cap-binding complex via association with the N-terminus of eIF4GI protein. Overexpression of the full-length of eIF4GI as well as of the N-terminus augments the Ago2-cap association, and the knock-down of eIF4GI by synthetic siRNAs decreases the Ago2-cap association in cells. Furthermore, the knock-down of eIF4GI de-represses the miRNA-mediated translational repression of capped poly(A)-tailed target mRNA. Finally, Cap photo-crosslinking assays confirm that Ago2 closely associates with cap structure, which is mediated by association with eIF4GI.In addition, I examine whether amino acid residues (Phe-470, Phe-505, Tyr-529, Lys-533 and Asp-537) previously suggested as requirements for the Ago2-cap association could be really involved in the Ago2-cap association. Cap-pulldown assays and cap-crosslinking assays demonstrate that the cap binding-like motif Ago2 (Phe-470 and Phe-505) is not critical for the Ago2-cap association. Similarly, the allosteric regulatory site Asp-537 equivalent to Asp-627 in Drosophila Ago2 does not influence both the Ago2-cap association, and the Ago2-mediated translational repression. Finally, I obtain the hypothetical structure of human Ago2 based on Aquifex aeolicus Ago through the PHYRE program, and find that Phe-294 and Tyr-805 can be potential players for regulation of the Ago2-cap association

Poly(alpha-hydroxy acids) 제제 생분해성 차폐막의 치주조직 재생유도 능력에 관한 조직학적 장기 관찰

The recent trend of research and development on guided tissue regeneration focuses on the biodegradable membranes, which eliminate the need for subsequent surgical removal. They have demonstrated significant and equivalent clinical improvements to the ePTFE membranes. This study evaluate guided tissue regeneration wound healing in surgically induced intrabony periodontal defects following surgical treatment with a synthetic biodegradable membranes, made from a copolymer of glycolide and lactide, in 8 beagle dogs. After full thickeness flap reflection, exposed buccal bone of maxillary and mandibular canine and premolar was removed surgically mesiodistally and occlusoapically at in size for preparation of periodontal defects. In experimental sites a customized barrier was formed and fitted to cover the defect. Flap was replaced slightly coronal to CEJ and sutured. Plaque control program was initiated and maintained until completion of the study. In 4, 8, 16 and 24 weeks after surgery, the animals were sacrificed and then undecalcified specimens were prepared for histologic evaluation. Histologic examination indicated significant periodontal regeneration characterized by new connective tissue attachment, cementum formation and bone formation. These membranes showed good biocompatibility throughout experiodontal period. The barriers had been completely resorbed with no apparent adverse effect on periodontal wound healing at 24 weeks. These results implicated that present synthetic biodegradable membrane facilitated guided tissue regeneration in periodontal defect.이 연구는 1996년도 서울대학교병원 임상공동연구비(1-96-75)의 지원에 의해 이루어졌습니다

Translation initiated by a ribosome recruited at downstream of a gene

2

Eukaryotic Translation Initiation Factor 4G Mediates MicroRNA-Regulated Translational Gene Silencing

1

IRES-dependent Translation of Bip mRNA is enhanced by an interaction of NSAP1 at heat stress condition

1

eIF4G determines the translational initiation site

1

Cell-Matrix adhesions of soft tissue cells around dental implants

The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality fir the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts adhesions to certain substrata can be explained by the 'focal adhesion' theory. On the other hand, epithelial cells adhere tn the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions' defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments